Water-bearing domestic appliance comprising a drainage pump and corresponding drainage pump

ABSTRACT

A water-bearing domestic appliance includes a retainer for retaining items to be subjected to a liquid treatment and a drainage pump having an inlet through which liquid enters the drainage pump. The drainage pump also includes an outlet through which liquid exits the drainage pump, a pump impeller for conveying liquid along a passage through the drainage pump extending from the inlet to the outlet, and a separate chamber located upstream of the pump impeller relative to the direction of flow of liquid through the passage. The separate chamber has an internal diameter and an external diameter and has respective radial bores on its external diameter and in the vicinity of its internal diameter.

The invention relates to a water-bearing domestic appliance comprising adrainage pump which has a pump impeller used to convey liquid and to adrainage pump with a pump impeller.

In water-bearing domestic appliances such as dishwashers or washingmachines a drainage pump is used to pump away dirty cleaning liquid. Atthe end of a drainage process air enters into the pump housing. Thissucked-in air is concentrated at the centre of the rotating pumpimpeller as a result of the pressure conditions and results in abreakaway or reduced conveying flow. Any remaining quantities of liquidare thus not pumped away by the drainage pump or are pumped away with adelay. Every drainage pump shows this problem which results in operatingdisturbances or requires other expensive or disadvantageous measures.

A ventilation device for a drainage pump in dishwashers is known fromthe German Utility Model 94 06 463 U1, which has a ventilation openingon the suction side for air enclosed at the centre of the drainage pumpto flow out. This ensures that functional disturbances on restarting thedrainage pump are avoided.

It is the object of the invention to provide a water-bearing domesticappliance of the type described wherein the conveyance of air and liquidand the pumping capacity of the drainage pump are improved and furtherto provide a corresponding drainage pump.

The object is solved according to the invention for the water-bearingdomestic appliance by the features of claim 1 and by the furtherindependent claim for the drainage pump. Further developments of theinvention are given in the dependent claims.

Starting from a water-bearing domestic appliance with a drainage pumpwhich has a pump impeller and a drainage pump with a pump impeller, thedraining pump according to the subject matter of the invention has aseparate chamber which is located behind the pump impeller in relationto the direction of flow of liquid and is equipped with respectiveradial bores on its external diameter and in the vicinity of itsinternal diameter. As a result of the separate chamber, a liquid flow isadvantageously formed from the external diameter to the internaldiameter and then into the centre of the pump impeller whereby the airis better vortexed with the liquid and the mixture thus formed is moreeffectively pumped away. The pumping capacity and the suction behaviourof the drainage pump are improved, especially without externalexpenditure and without delaying of the conveying medium caused byventilation openings or ventilation channels in the pump housing.

According to a favourable further development of the invention, theseparate chamber is arranged as close as possible to the pump impeller.The liquid flow in the flow circuit of the drainage pump from theexternal diameter to the internal diameter of the separate chamber andfrom there to the centre of the pump impeller for mixing liquid with aircan thus be further improved.

According to a further favourable embodiment of the invention, aplurality of bores are provided for the external diameter and theinternal diameter. The bores for the external diameter and internaldiameter are preferably provided so that they are each distributeduniformly on the separate chamber. Both measures positively influencethe liquid flow in relation to the flow circuit of the drainage pump.

A further embodiment of the invention whereby the bores have a smallcross-section has proved to be of particular value.

The previously described features are advantageously also used in thedrainage pump with an impeller according to the invention and especiallyin dishwashers and washing machines.

The invention provides a water-bearing domestic appliance with adrainage pump which has a pump impeller used to convey liquid, whereinthe conveyance of air and liquid and the pump capacity of the drainagepump are improved and further provides a corresponding drainage pumpwith a pump impeller.

The subject matter of the invention is explained in detail withreference to an exemplary embodiment shown in the figures. In detail thefigures show:

FIG. 1 a drainage pump of a water-bearing domestic appliance accordingto the invention and

FIG. 2 shows a section of the chamber pertaining to the drainage pumpwith an exemplary arrangement of bores.

FIG. 1 show a drainage pump 1 according to the invention of awater-bearing domestic appliance according to the invention, which isnot shown in detail, typically a dishwasher or a washing machine, whichhas a pump housing 2 with a pump impeller 3. An inlet connecting piece 4via which liquid, for example water, can be conveyed into the pumpimpeller 3 or air can be sucked in, runs in the direction of the axis ofthe pump impeller 3 and is moulded on the input side of the pump housing2. A motor housing 5 with the drive motor for the pump impeller 3 forexample with straight vanes which can be set in rotation is also locatedin the direction of the axis of the pump impeller 3 and is moulded onthe other side of the pump housing 2. The drainage pump 1 also has anoutlet connecting piece 10 which is arranged radially in relation to theaxis of the pump impeller 3.

According to the subject matter of the invention, the water-bearingdomestic appliance has a drainage pump 1 with a separate chamber 6 whichis located behind the pump impeller 3 in relation to the direction ofthe conveyed liquid, i.e., the axis of the pump impeller 3, and isprovided with respective radial bores 7′ and 7″ on its external diameter11 and in the vicinity of its internal diameter 12. As a result of theseparate chamber 6, a liquid flow, identifiable from the arrows in FIG.1, is advantageously produced from the external diameter 11 to theinternal diameter 12 and then into the centre 9 of the pump impeller 3,whereby the air is better vortexed with the liquid and the mixture 8thus produced is pumped away more effectively. The pump capacity and thesuction behaviour of the drainage pump 1 are improved, especiallywithout external expenditure and without any delay of the conveyingmedium caused by ventilation openings or ventilation channels in thepump housing 2.

In a favourable fashion the separate chamber 6 is arranged as close aspossible to the pump impeller 3 whereby the liquid flow in the flowcircuit—see arrows—of the drainage pump 1 from the external diameter 11to the internal diameter 12 of the separate chamber 6 and from there tothe centre 9 of the pump impeller 3 for mixing liquid with air can thusbe further improved. A plurality of bores 7′, 7″ are provided for theexternal diameter 11 and the internal diameter 12 and preferablyprovided so that they are each distributed uniformly on the separatechamber 6. Both measures positively influence the liquid flow—seearrows—in relation to the flow circuit of the drainage pump 1.

For illustration FIG. 2 shows a section of the separate chamber 6pertaining to the drainage pump with an exemplary arrangement of bores.Thus, one bore 7′ is located on the external diameter 11 of the chamber6 whereas another bore 7″ is located near the internal diameter 12 ofthe chamber 6. In total, the chamber 6 has respectively four uniformlydistributed radial bores 7′ and 7″ both on its external diameter 11 andalso on its internal diameter 12. The arrows show the behaviour of theliquid flow from the external diameter 11 with bore 7′ where a higherpressure prevails to the internal diameter 12 with bore 7″ where a lowerpressure prevails and from there to the centre of the pump impeller. Ithas proved to be of particular value if the bores have a smallcross-section so that all the bores have a diameter of 3.5 mm each forexample.

The invention provides a water-bearing domestic appliance with adrainage pump 1 which has an impeller wheel 3 used to convey liquid,wherein the conveyance of air and liquid and the pump capacity of thedrainage pump 1 are improved and further provides a correspondingdrainage pump 1 with a pump impeller 3.

1-14. (canceled)
 15. A water-bearing domestic appliance comprising: aretainer for retaining items to be subjected to a liquid treatment: anda drainage pump having an inlet through which liquid enters the drainagepump, an outlet through which liquid exits the drainage pump, a pumpimpeller for conveying liquid along a passage through the drainage pumpextending from the inlet to the outlet, and a separate chamber locatedupstream of the pump impeller relative to the direction of flow ofliquid through the passage, the separate chamber having an internaldiameter and an external diameter and having respective radial bores onits external diameter and in the vicinity of its internal diameter. 16.The water-bearing domestic appliance according to claim 15, wherein theseparate chamber is located relatively closely adjacent the pumpimpeller.
 17. The water-bearing domestic appliance according to claim15, wherein a respective plurality of bores are provided on the externaldiameter of the separate chamber and another respective plurality ofbores are provided on the internal diameter of the separate chamber. 18.The water-bearing domestic appliance according to claim 15, wherein thebores for the external diameter and the internal diameter aredistributed uniformly on the separate chamber.
 19. The water-bearingdomestic appliance according to claim 15, wherein each of the bores hasa small cross-section.
 20. The water-bearing domestic applianceaccording to claim 15, wherein the water-bearing domestic appliance is adishwasher and the retainer for retaining items to be subjected to aliquid treatment is operable to retain items to subjected to adishwasher liquid treatment.
 21. The water-bearing domestic applianceaccording to claim 15, wherein the water-bearing domestic appliance is awashing machine and the retainer for retaining items to be subjected toa liquid treatment is operable to retain items to subjected to a washingmachine liquid treatment.
 22. A drainage pump comprising: an inletthrough which liquid enters the drainage pump; an outlet through whichliquid exits the drainage pump; a pump impeller for conveying liquidalong a passage through the drainage pump extending from the inlet tothe outlet; and a separate chamber located upstream of the pump impellerrelative to the direction of flow of liquid through the passage, theseparate chamber having an internal diameter and an external diameterand having respective radial bores on its external diameter and in thevicinity of its internal diameter.
 23. The drainage pump according toclaim 22, wherein the separate chamber is located relatively closelyadjacent the pump impeller.
 24. The drainage pump according to claim 22,wherein a respective plurality of bores are provided on the externaldiameter of the separate chamber and another respective plurality ofbores are provided on the internal diameter of the separate chamber. 25.The drainage pump according to claim 22, wherein the bores for theexternal diameter and the internal diameter are distributed uniformly onthe separate chamber.
 26. The drainage pump according to claim 22,wherein each of the bores has a small cross-section.
 27. The drainagepump according to claim 22, wherein the drainage pump is operable in awater-bearing domestic appliance in the form of a dishwasher.
 28. Thedrainage pump according to claim 22, wherein the drainage pump isoperable in a water-bearing domestic appliance in the form of a washingmachine.